After college, Milligan worked as an engineer at the Edgemoor Power Plant of
Delmarva Power and Light Company in
Wilmington, Delaware, not far from where he grew up. At that time, he decided to try his hand at boxing. For that reason he came to Wilmington's West Center City Warriors, where he was trained by John Thornton. Despite having no prior background in boxing, Milligan had an outstanding amateur career, and in 1983 he won the National
AAU Heavyweight Championship. Being a white,
Ivy League-educated boxer attracted a lot of attention to him, and he was featured in numerous newspaper and magazine articles nationwide, including
People Magazine and
Sports Illustrated. He also defeated
Henry Tillman, the 1984 Olympic Heavyweight Gold Medalist, in the 1983 National finals in
Colorado Springs, Colorado. He entered the 1984 U.S. Olympic trials seeded first in the 201 pound class, despite weighing only 184 pounds, but lost in the semi-finals to 17-year-old
Mike Tyson on June 9, 1984. Milligan was leading on points when Tyson stopped him in the second round. His manager was Charlie Messina.
Wesley Watson, who lived on Washington Street before joining the Army, came to the West Center City Community Center one night and sparred against Milligan," Messina said.
Highlights Local match-up (201 lbs), October 1981 (debut): • Defeated Gary Wright KO 1 Local match-up (201 lbs), March 1982: • Defeated Tyrone Armstrong RSC 3 Pennsylvania Golden Gloves (201 lbs),
Zembo Mosque,
Harrisburg, Pennsylvania, March 1982: • Defeated Clinton Barnes RSC 1
National Golden Gloves (201 lbs),
Kansas City, Missouri, March 1982: • 1/16: Defeated Michael Arms RSC • 1/8: Defeated Bryan Westmoreland RSC • 1/4: Defeated
Orlin Norris • 1/2: Lost to Mike Dennard by split decision, 2–3 Local match-up (201 lbs),
Resorts International Hotel & Casino,
Atlantic City, New Jersey, 1982: • Defeated Ernie Singleton by decision Mid-Atlantic ABF Championships (201 lbs), Brandywine Club,
Chadds Ford, Pennsylvania, October 1982: • 1/2: Defeated Sam Green (4 rds) • Finals: Defeated Ernie Singleton RSC 3 AAU Region #2 Championships (201 lbs),
Hazlet, New Jersey, November 1982: • Finals: Defeated n/a
United States National Championships (201 lbs),
Indianapolis, Indiana, December 1982: • 1/8: Defeated
Loi Faateete RSC 2 • 1/4: Defeated Joey Christjohn KO 3 • 1/2: Lost to Richard Johnson by split decision, 2–3 Sweden–USA Duals (201 lbs),
Stockholm, Sweden, January 1983: • Defeated Jack Johnsen (Sweden) RSC 2 Sweden–USA Duals (201 lbs),
Gothenburg, Sweden, January 1983: • Defeated Nasser Hassanzadeh (Sweden) RSC 1 Norway–USA Duals (201 lbs), 1983: • Defeated Magne Havnaa in Oslo. Havnaa would later be WBO Cruiserweight world champion as a pro.
National Sports Festival (201 lbs),
U.S. Olympic Training Center,
Colorado Springs, Colorado, June 1983: • 1/2: Lost to
Henry Tillman RSC 2 AAU Region #2 Championships (201 lbs), Radisson Hotel,
Wilmington, Delaware, October 1983: • Defeated
Michael Bentt by split decision, 3–2
United States National Championships (201 lbs),
Colorado Springs, Colorado, November 1983: • 1/8: Defeated
Henry Tillman by split decision, 3–2 • 1/4: Defeated
Al Evans KO 1 • 1/2: Defeated Avery Rawls by unanimous decision, 5–0 • Finals: Defeated Olian Alexander by unanimous decision, 5–0 USA–Yugoslavia Duals (201 lbs),
Shreveport, Louisiana, January 1984: • Defeated n/a Yugoslavia–USA Duals (201 lbs),
Rijeka,
Yugoslavia, February 1983: • Lost to
Xhevdet Peci (Yugoslavia) DQ 2 Yugoslavia–USA Duals (201 lbs),
Borovo,
Yugoslavia, February 1983: • Defeated Milenko Andrić (Yugoslavia) KO 1 National Olympic Trials (201 lbs),
Tarrant County Convention Center,
Fort Worth, Texas, June 1984: • 1/4: Defeated Charles Dread RSC 1 • 1/2: Lost to
Michael Tyson RSC 2 He ended his amateur career with a record of 41 wins (31 knockouts,) 6 losses. ==Professional career==